The present invention relates, in general, to optical scanning systems and more particularly to an optical system for reading bar codes on documents such as checks.
The use of optical bar codes printed on financial documents is well-established in the banking industry and in processing of which documents, optical readers are employed. Ideally, the presence of a bar would be indicated by one of two states, and the absence of a bar would be indicated by the other of two states. In processing these documents, speed in reading is a critical requirement. Due to limitations in printing the bars on documents, during which ink splatter and smudging of the bar occurs, prior bar code readers have been unable to process the document at the desired speed. Other problems encountered in reading these documents include endorsement indicia stamped by the bank over the bar code, the color and quality of the paper and the presence of a design printed on the document on which the bar code is printed. Further problems include the printing of bars which are not vertical and the skewed condition of the document when in a reading position. In order to reduce the cost of printing coded bars on a document, matrix printers have been employed for printing bars comprising a row of dots and using fluorescent ink to increase the light density reflected from the dots. Using a single-slot type read head in reading bars printed by this type of printing process still has not overcome the above-cited problems. It is therefore a principal object of this invention to provide a bar code reader which overcomes the above-cited problems in bar code printing. It is a further object of this invention to provide a bar code reader for accurately detecting the presence of a bar on a document traveling at a relatively high rate of speed. It is another object of this invention to provide a bar code reader whose construction is relatively simple and therefore low in cost.